An image forming apparatus includes a recording head and a host control system. The recording head eject inks. The host control system controls the recording head. The recording head includes a heater, a temperature sensor, a switching element on a power line to the heater, and a controller configured to control the switching element on the basis of a measurement temperature of the temperature sensor and thereby control temperature of the recording head. Further, the host control system includes a current detection unit configured to detect a current that flows in the power line, a system-side switching element arranged on upstream side of the power line from the switching element, and a main controller configured to cut off the current using the system-side switching element if a continuous current flow time of the current detected by the current detection unit exceeds a predetermined value.

wherein the pressure compartment substrate, the diaphragm, the first common electrode, the first thin-film piezoelectric body, the individual electrode, the second thin-film piezoelectric body, and the second common electrode are stacked in this order from a lower side toward an upper side, and in a contraction period, which is a period of applying the reference voltage and the drive voltage for causing the pressure compartment to contract for liquid ejection, a displacement amount of the first thin-film piezoelectric body is smaller than a displacement amount of the second thin-film piezoelectric body.

wherein the pressure compartment substrate, the diaphragm, the first common electrode, the first thin-film piezoelectric body, the individual electrode, the second thin-film piezoelectric body, and the second common electrode are stacked in this order from a lower side toward an upper side, and in a contraction period, which is a period of applying the reference voltage and the drive voltage for causing the pressure compartment to contract for liquid ejection, a displacement amount of the first thin-film piezoelectric body is larger than a displacement amount of the second thin-film piezoelectric body.

A head unit includes an ejection unit configured to eject a liquid in accordance with a drive signal, and a drive unit supplied with a power supply voltage from outside and configured to output the drive signal, wherein the drive unit includes a first step-down circuit configured to step down the power supply voltage to output a first drive voltage, a second step-down circuit configured to step down the power supply voltage to output a second drive voltage, an output circuit supplied with the first drive voltage and configured to output the drive signal according to the first drive voltage, and a drive control circuit supplied with the second drive voltage and configured to control drive of the output circuit in accordance with the second drive voltage.

In the inkjet recording apparatus, during execution of a correction mode, an image reading part reads a check chart for density measurement recorded on a sheet by a recording part, whereby a controller acquires density information about recording heads. The controller also repeatedly corrects a drive condition for the recording heads until the acquired density information about the recording heads comes to not more than a predetermined threshold value. When the drive condition for the recording heads has been corrected to a specified number of times, it is decided whether or not the density information about the recording heads has been converging toward a specified value each time the drive condition for the recording heads is corrected, where given that the density information about the recording heads has not been converging toward the specified value, the threshold value is changed.

In an image forming apparatus, a recording element group is configured to eject ink correspondingly to a driving voltage, and a density adjusting unit is configured to (a) cause to eject ink for a first test chart with a first driving voltage and causes to eject ink for a second test chart with a second driving voltage that is different from the first driving voltage, (b) acquire a density of the first test chart and a density of the second test chart, (c) derive a difference between the density of the first test chart and the density of the second test chart, and (d) derive a driving voltage corresponding to a target density on the basis of the difference between the density of the first test chart and the density of the second test chart and a difference between the first driving voltage and the second driving voltage.

A power supply control apparatus comprises a first power supply supplying power to a controller and a second power supply supplying power to an operation unit and a power controller. The operation unit receives an operation for switching the first power supply on and off. The power controller is operable to turn on the first power supply according to the signal from a timer or the operation by the operation unit, and to turn off the first power supply according to a state of the controller. The controller, upon at least either of the operation by the operation unit or the signal from the timer, performs a setting to the timer of a time at which to turn on the power from the first power supply or a time at which to turn off the power from the first power supply.

There is provided image formation method for forming image on medium by discharging liquid from head having nozzles arranged in first direction and actuators corresponding respectively to the nozzles. The method includes: discharging the liquid onto the medium from the nozzles by applying first voltage to the actuators while performing relative displacement between the head and the medium in second direction intersecting the first direction; and applying second voltage higher than the first voltage to actuator, of the actuators, corresponding to correction nozzle, based on information identifying discharge defect nozzle being a nozzle, of the nozzles, unable to discharge the liquid normally, the correction nozzle being a nozzle, of the nozzles, adjacent to the discharge defect nozzle in the first direction.

An electrohydrodynamic (EHD) printing system may include a nozzle having a nozzle opening, a discharge electrode, a voltage source, an imager, and a controller in communication with the voltage source and the imager. The nozzle may be configured to contain ink and discharge the ink through the nozzle opening. The discharge electrode may be configured to be in electrical communication with the ink in the nozzle to apply voltage to the ink and create a jet of the ink discharged from the nozzle opening. The voltage source may be configured to apply the voltage to the discharge electrode. The imager may be configured to image the jet of the ink discharged. The controller may be configured to analyze the images from the imager and output control signals to the voltage source based on an analysis of the images.

There is provided an image recording apparatus including: a recording head unit; a head support; a power supply trace; and a ground trace. The recording head unit includes: a portion of the power supply trace; a portion of the ground trace; a drive circuit to which a voltage is supplied via the power supply trace; a recording element to which a drive voltage is applied by the drive circuit and to which the ground trace is connected; and a capacitive element.